DE102012223530A1 - Monitoring circuit for measuring e.g. temperature of battery module in lithium ion battery of motor car, has series arrangement formed from resistor and switching unit, where ends of arrangement are electrically connected with terminal - Google Patents

Abstract

The circuit (30) has two terminals (11, 12) for connection with buses of a bus system. A transceiver circuitry (20) is connected with the two terminals, and a control electronic unit (10) communicates with external control units and the transceiver circuitry. The circuit is connected with a battery cell of a battery module. A series arrangement (8) is formed from a line terminal resistor (5) and a switching unit (6) i.e. MOSFET, where ends of the series arrangement are electrically connected with one of the two terminals. The switching unit is controlled over the electronic unit. Independent claims are also included for the following: (1) a monitoring system (2) a method for initializing a monitoring system.

Description

The present invention relates to a monitoring circuit for a battery module, which is connectable to a bus system and which has a controllable line termination resistor for the termination of the bus lines of the bus system and a monitoring system with monitoring circuits according to the invention and a method for performing the line termination in the initialization of the monitoring system.

State of the art

In a battery management system of the prior art for the management of the battery of an electric or hybrid vehicle, the individual cell voltages and / or the temperatures of battery modules or battery cells must be measured and monitored based on current safety concepts. According to the prior art, this is done separately for each battery cell, wherein a monitoring circuit or cell monitoring electronics (CSC - Cell Sense Circuit) is integrated per battery module. These monitoring circuits are constructed according to the installation situation and granularity of the battery pack or the battery according to modular or scalable. Each of the monitoring circuits must be able to communicate with a central (battery) control unit (BCU). The bus system or the communication bus required for this purpose can be designed differently according to the prior art. In automotive applications, for example, the CAN bus (CAN - Controller Area Network) has become established.

The CAN bus is a multi-vendor and after ISO 11898 specified digital bus system. It is mainly used in automobiles for communication between different ECUs. In the physical layer of the CAN bus, the digital information is transmitted over two bus lines with opposite voltage levels. When a logical one is transmitted, the driver circuit or the transceiver circuit sets the two bus lines, which are designated as CAN HIGH and CAN LOW, to high-resistance to a rest potential of VCC / 2 or 2.5 V (recessive state, differential voltage equals zero). When transmitting the complementary information - a logical zero - the transceiver circuit increases the voltage of CAN HIGH (to approx. 3.5 V) and at the same time reduces the potential of CAN LOW (to approx. 1.5 V). This signal level (differential voltage> 1 V) of the two bus lines is referred to as a so-called dominant state.

The CAN bus as well as most bus systems of the prior art must be terminated or terminated at the ends of their bus lines with a characteristic impedance or a line terminating resistor in order to avoid so-called reflections of the incoming signal at the ends of the bus system. If the bus line was incorrectly terminated, the signal would return to the line and interfere with other signals. The line termination or the line terminating resistor in each case within the monitoring circuits is firmly soldered according to the prior art in the ends of the bus lines of the bus system. In other embodiments of the prior art, the monitoring circuits at the ends of the bus lines provide a corresponding line termination resistor placement option.

The latter has the disadvantage that not all battery modules can be treated as so-called equal parts (variant variety). Alternatively, it is possible to realize the line termination via an electronic or mechanical coding. However, both of these alternatives also have the effect that a battery module can no longer be treated as a common part during system integration, since either the hardware or the software of battery modules designed in this way differ from each other. The ease of maintenance of such systems is rather low.

The addressing of the monitoring circuits, which are connected to a bus system of the prior art, is ensured by an addressing method in the context of the controlled run-up of the modules. In this case, a position-equal monitoring circuit or the battery cell block to be monitored by the latter are assigned the same unique identification number. The control of the addressing process is usually carried out by the central control unit, which communicates via a hardware line with the control electronics of the monitoring circuits. To execute the addressing method, an activation signal is first transmitted from the central control unit to the control electronics of the first monitoring circuit. The initialization and the assignment of the unique identification number to the first monitoring circuit are then carried out via this control electronics. After completion of the addressing of the first monitoring circuit, the activation signal is forwarded by the latter to the control electronics of a further monitoring circuit and the addressing thereof is carried out. The addressing procedure is completed as soon as all monitoring circuits to be activated activate the activation signal received and assigned a unique identification number.

Disclosure of the invention

According to the invention, a monitoring circuit for a battery module is provided, which comprises two connections for the connection to the bus lines of a bus system. Furthermore, the monitoring circuit comprises a transceiver circuit, which is connected to the two terminals and adapted to respond to the reception of a logical signal with a corresponding change in the potentials at the terminals. Furthermore, the monitoring circuit has an electronic control unit, which is designed to communicate with external control units and the transceiver circuit, wherein the monitoring circuit with at least one battery cell of a battery module is connectable and adapted to the temperature and / or the voltage of at least one to measure their connected battery cell.

According to the invention, the monitoring circuit has a series connection of a line terminating resistor and a switching means, wherein the ends of the series circuit are each electrically connected to one of the two terminals.

By means of such a monitoring circuit configured, it is possible to make a termination of a bus system within the monitoring circuit by the addition of the line termination resistor optional. If a bus system or a monitoring system realized with monitoring circuits according to the invention, a specially made harness with soldered line terminating resistors is no longer needed. In addition, all monitoring circuits or battery modules can then be produced as equal parts with regard to both the hardware and the software components. As a result, the maintainability and the commissioning of such monitoring systems are greatly simplified. Furthermore, the bus lines of the bus system are always optimally completed during the startup phase at the active end of the bus lines, whereby an improvement in the interference of the bus system is achieved.

In a preferred embodiment, the switching means via the control electronics can be controlled. As a result, the switching means is thus controlled by an electronic unit which is located within the monitoring circuit and does not have to be controlled by an external component.

Preferably, the control electronics is adapted to cause the activation of the monitoring circuit and / or the closing of the switching means upon receipt of a control signal. This ensures that the bus lines, for example, during the addressing process, are terminated within the monitoring circuits, if necessary.

Preferably, the series connection is arranged within the transceiver circuit. As a result, the line terminating resistor can be produced as a component together with the transceiver circuit and can also be replaced together with it in the event of damage, which can save costs.

In a preferred embodiment, the switching means is designed as a MOSFET, which operates in low-side operation. Since the MOSFET with its source terminal connected to the bus line of the low potential bus system and its drain terminal connected via a termination resistor to the other higher potential bus line, the MOSFET operates in low side operation. MOSFETs are inexpensive and very compact, that is, in a high integration density feasible. Furthermore, MOSFETs have fast switching time as well as stable amplification and response times.

Furthermore, a monitoring system is provided which comprises a central control unit which is connected to the two bus lines of a bus system and comprises at least two monitoring circuits according to the invention, which are each connected via their two terminals to the two bus lines of the bus system. The monitoring system further comprises a hardware line via which the control electronics of the at least two monitoring circuits are connected to each other and to the central control unit.

In a preferred further development of this embodiment, the central control unit is embodied as a battery management system and alternatively or additionally comprises a transceiver circuit and, alternatively or additionally, a line termination resistor, via which the central control unit is connected to the bus lines of the bus system. As a result, the bus system is also terminated on the input side via the central control unit by a line terminating resistor.

Furthermore, a method for initializing a monitoring system is provided which comprises a monitoring system according to the invention. The method comprises the following method steps: activating a first of the at least two Monitoring circuits via a transmitted via the hardware line activation signal by the central control unit, closing the switching means of the activated monitoring circuit by the control electronics of the activated monitoring circuit, establishing a communication between the control electronics of the activated monitoring circuit and the central control unit. Assigning a unique identification number to the activated monitoring circuit by the central control unit, opening the switching means of the activated monitoring circuit by the control electronics of the activated monitoring circuit, transmitting an activation signal via the hardware line from the control electronics of the activated monitoring circuit to the control electronics of another deactivated monitoring circuit, restarting the method comprising the step of closing the switching means of the further monitoring circuit. Such a method makes it possible to carry out an optimized addressing of the monitoring circuits of a monitoring system. Since with each assignment of a unique identification number to one of the monitoring circuits, a simultaneous termination of the bus lines of the bus system within the respective monitoring circuit can be made, the immunity of the bus system improves during the addressing process.

In a preferred further development of the above method for initializing a monitoring system, the method further comprises the step of terminating the method as soon as all monitoring circuits of the monitoring system are activated. This defines a meaningful end condition for the procedure.

In a preferred further development of this or of the preceding method for initializing a monitoring system, the method is controlled by the central control unit.

Further, a battery is provided with a monitoring system according to the invention, wherein the battery is particularly preferably designed as a lithium-ion battery. Advantages of such batteries include their comparatively high energy density and their high thermal stability. Another advantage of lithium-ion batteries is that they are not subject to memory effect.

Furthermore, a motor vehicle with a battery is provided with a monitoring system according to the invention, wherein the battery is connected to a drive system of the motor vehicle.

Advantageous developments of the invention are specified in the subclaims and described in the description.

drawings

Embodiments of the invention will be explained in more detail with reference to the drawings and the description below. Show it:

1 An embodiment of a monitoring circuit according to the invention for a battery module,

2 an embodiment of the series connection of a monitoring circuit according to the invention, and

3 an embodiment of a monitoring system according to the invention.

Embodiments of the invention

In the 1 is an embodiment of a monitoring circuit according to the invention 30 for a battery module. The monitoring circuit 30 has two connections 11 . 12 via which it can be connected to the bus lines of a bus system. Such a bus system can be designed purely as a CAN bus. The connection 11 is then purely exemplary with the first bus line of the CAN bus system, which is referred to here as CAN-High and the connection 12 with the second bus line of the CAN bus system, which is referred to here as CAN low, connectable. Furthermore, the monitoring circuit 30 a transceiver circuit 20 on that with a first and a second of the connectors 11 . 12 connected and adapted to receive a logical signal with a corresponding change in the potentials at the terminals 11 . 12 to react. Is the monitoring circuit 30 So with the two bus lines, for example, connected to those of a CAN bus system, is also the transceiver circuit 20 connected to these bus lines. The transceiver circuit 20 is designed to be connected via the bus lines or those connected to them 11 . 12 received signal with a change in the potential at one or both of the terminals 11 . 12 to respond in response to the respective received signal. Like the transceiver circuit 20 the potential at the terminals 11 . 12 changed, so depends on the nature of the received signal. Here is the transceiver circuit 20 both to a rectified, for example equal increase or decrease of the potential at both terminals 11 . 12 , as well as to a different change in the potential at the terminals 11 . 12 in a position. That's how it works the transceiver circuit 20 for example, starting from an output potential of the two terminals 11 . 12 , upon receipt of a certain type of signal, the potential of one terminal 11 while raising the potential of the other connector 12 reduced. By way of example, the transceiver circuit 20 for example, when receiving a logical one, the two ports 11 . 12 to a quiescent potential of the supply voltage while, upon receiving a logic zero, the potential at a terminal 12 increased and at the other connection 11 reduced. Like the transceiver circuit 20 is responsive to the reception of a logical signal is chosen purely by way of example in this embodiment and may differ from the manner set forth in this embodiment.

Furthermore, the monitoring circuit 30 an electronic control system 10 which is designed to with external control units and the transceiver circuit 20 to communicate. In other words, the control electronics 10 both configured to send signals to external control units, for example to an external, central control unit, such as a battery management system purely by way of example, as well as to receive from these. Furthermore, the control electronics 10 designed to send signals to the control electronics 10 from other monitoring circuits 30 to transmit or receive from them.

The monitoring circuit 30 is connected in this embodiment with a battery module, not shown, which has purely by way of example six battery cells. Furthermore, the monitoring circuit 30 connected in this embodiment with all six battery cells or with the electrodes of these six battery cells of the battery module (not shown). Furthermore, the monitoring circuit 30 designed in this embodiment to measure the temperatures and the individual voltages of the six battery cells. Furthermore, the monitoring circuit 30 in this embodiment, the measured or determined voltage and temperature data to an external, central control unit (not shown) to transmit. Both the number of battery cells and the connection to the battery module is for a monitoring circuit according to the invention 30 optional and chosen purely by way of example in this embodiment. It can also monitor circuits according to the invention 30 be realized, in which a monitoring circuit 30 only with one or even with n battery cells and not connected to the battery module in which the battery cells are installed. Furthermore, the monitoring circuit 30 also for detecting further parameters of a battery cell, apart from the individual voltage and temperature, be formed.

The monitoring circuit 30 has a series connection 8th from a line termination resistor 5 and a switching means 6 on, with the ends of the series connection 8th each with one of the two connections 11 . 12 are electrically connected. In other words, the series connection is 8th from the switching means 6 and the line termination resistor 5 between the connections 11 . 12 connected. The connections 11 . 12 So are about the switching means 6 with each other, via the line termination resistor 5 , connectable. Are the connections 11 . 12 each connected via a bus line to a bus system, this can thus be within the monitoring circuit 30 by closing the switching means 6 terminate. Is the switching means 6 closed, are the two connections 11 . 12 and thus the bus lines electrically via the line termination resistor 5 connected.

In this embodiment, the switching means 6 via the control electronics 10 controllable. Furthermore, the control electronics 10 adapted to receive the activation of the monitoring circuit upon receipt of a certain kind of control signal, for example an activation signal 30 and concomitantly, the closing of the switching means 6 to induce. This is just like the controllability of the switching means 6 through the control electronics 10 , for a monitoring circuit according to the invention 30 however optional. The control electronics 10 may also be adapted to the activation of the monitoring circuit 30 and the closing of the switching means 6 separate from each other.

The 2 shows an embodiment of the series circuit 8th a monitoring circuit according to the invention 30 of the 1 , In this case, the ends of the series circuit 8th each with a connection 11 . 12 the monitoring circuit 30 connected. The switching means 6 is in this embodiment as a MOSFET, more precisely as an N-channel MOSFET 6 whose gate terminal is connected to the drain terminal of another as a MOSFET, more specifically, as a P-channel MOSFET, executed switching means and a terminal of a gate resistor. The other terminal of the gate resistor is connected to the source terminal of the switching means 6 and the series connection 8th connected. The gate terminal of the further, designed as a P-channel MOSFET switching means is connected to the collector of a bipolar transistor designed as switching means whose emitter with the ground and its base in this embodiment purely by way of example with the control electronics 10 the monitoring circuit 30 connected is. This embodiment of the series connection 8th a monitoring circuit according to the invention 30 is chosen purely by way of example and can be executed in any other way. Also when using a MOSFET for the switching means 6 can the execution of its drive circuit within a monitoring circuit according to the invention 30 can be done arbitrarily according to the prior art.

The 3 shows an embodiment of a monitoring system according to the invention 60 , This monitoring system 60 has three monitoring circuits according to the invention 30 two of which are shown executed while the third monitoring circuit 30 is merely indicated. The monitoring circuits according to the invention 30 are executed as in the description of the 1 explained. The like designated components correspond to those of the first embodiment of 1 , so that what is said there on the embodiment of the 3 is to be transferred. The monitoring system 60 has a bus system 40 on which two bus lines 38 . 39 are shown. These bus lines 38 . 39 are each with the connections 11 . 12 the monitoring circuits according to the invention 30 electrically connected. Furthermore, the bus lines 38 . 39 in this embodiment, the input side with a central control unit 50 connected, which one for a monitoring system according to the invention 60 optional, fixed to the bus lines 38 . 39 connected line termination resistor 5 as well as an optional, also with the bus lines 38 . 39 connected transceiver circuit 20 having. Here is the central control unit 50 as the monitoring circuits according to the invention 30 with closed switching means 6 , via the line terminator 5 as well as the transceiver circuit 20 with the bus lines 38 . 39 connected. The connections of the line termination resistor 5 of the central controller 50 So are each with one of the two bus lines 38 . 39 connected, which input side to the transceiver circuit 20 of the central controller 50 are connected.

Furthermore, the monitoring system 60 a hardware line 35 on which the control electronics 10 of the three monitoring circuits 30 with each other and with the central control unit 50 are connected. In the embodiment of 3 the control electronics are capable 10 all monitoring circuits 30 via an optional switching means the interruption of the hardware line 35 to induce. Are those for a surveillance system according to the invention 60 optional switching means closed, for example, an activation signal, which via the hardware line 35 on the control electronics 10 a monitoring circuit 30 is applied by this control electronics 10 to the control electronics 10 another monitoring circuit 30 be transmitted.

For an initialization of the monitoring system according to the invention 60 , which in this embodiment purely by way of example of the central control unit 50 is controlled, this first generates an activation signal and transmits the same, over the hardware line 35 , to the control electronics 10 a first of the three monitoring circuits 30 , whereby the same is activated. Simultaneously with the activation of the monitoring circuit 30 initiates their control electronics 10 the closing of the switching means 6 so the bus lines 38 . 39 over the connections 11 . 12 within the activated monitoring circuit 30 are terminated. Then a communication between the control electronics 10 the activated monitoring circuit 30 and the central controller 50 over the hardware line 35 built up. Is the communication between the central controller 50 and the monitoring circuit 30 constructed, has the central control unit 50 the activated monitoring circuit 30 a unique identification number. So there is a unique identification number to the activated monitoring circuit 30 forgive. If this allocation has taken place, the control electronics 10 the activated monitoring circuit 30 the opening of the switching means 6 that concludes in the hardware line 35 lying, optional switching means and transmitted in this way the activation signal via the hardware line 35 to the control electronics 10 the adjacent, further deactivated monitoring circuit 30 , This will make this further monitoring circuit 30 activated and already with a first of the monitoring circuits 30 performed procedure begins, now with this further monitoring circuit 30 Again with the step of closing the switching means 6 this further monitoring circuit 30 , With this further and with the third of the monitoring circuits 30 of the monitoring system 60 Then an initialization as above for the first of the monitoring circuits 30 described carried out. The central control unit 50 the initialization in this embodiment stops only when all monitoring circuits 30 of the monitoring system 60 are activated and assigned a unique identification number. The order to open and close the switching means 6 and the switching means for forwarding the hardware line 35 may vary.

An inventive monitoring system 60 may also only two or even more than three, for example 4 or n monitoring circuits according to the invention 30 include.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited non-patent literature

• ISO 11898 [0003]

Claims (13)

Monitoring circuit ( 30 ) for a battery module, comprising - two terminals ( 11 . 12 ), for connection to the bus lines ( 38 . 39 ) of a bus system ( 40 ), - a transceiver circuit ( 20 ), which with the two connections ( 11 . 12 ) and adapted to receive a logical signal with a corresponding change in the potentials at the terminals ( 11 . 12 ), - a control electronics ( 10 ), which is designed with external control units and the transceiver circuit ( 20 ), the monitoring circuit ( 30 ) is connectable to at least one battery cell of a battery module and adapted to measure the temperature and / or the voltage of at least one battery cell connected to it, characterized in that the monitoring circuit ( 30 ) a series connection ( 8th ) from a line termination resistor ( 5 ) and a switching means ( 6 ), wherein the ends of the series circuit ( 8th ) each with one of the two connections ( 11 . 12 ) are electrically connected. Monitoring circuit ( 30 ) according to claim 1, wherein the switching means ( 6 ) via the control electronics ( 10 ) is controllable. Monitoring circuit ( 30 ) according to one of the preceding claims, wherein the control electronics ( 10 ) is adapted to activate the activation of another monitoring circuit ( 30 ) and / or the closing of the switching means ( 6 ) upon receipt of a control signal. Monitoring circuit ( 30 ) according to one of the preceding claims, wherein the series circuit ( 8th ) within the transceiver circuit ( 20 ) is arranged. Monitoring circuit ( 30 ) according to one of the preceding claims, wherein the switching means ( 6 ) works in high-side mode. Monitoring circuit ( 30 ) according to one of the preceding claims, wherein the switching means ( 6 ) works in low-side mode. Monitoring system ( 60 ), comprising - a central control unit ( 50 ), with the two bus lines ( 38 . 39 ) of a bus system ( 40 ), - at least one monitoring circuit ( 30 ), which are designed according to one of the preceding claims and have their two connections ( 11 . 12 ) with the two bus lines ( 38 . 39 ) of the bus system ( 40 ), the monitoring system ( 60 ) a hardware line ( 35 ), via which the control electronics ( 10 ) of the monitoring circuit ( 30 ) with the central control unit ( 50 ) connected is. Monitoring system ( 60 ) according to claim 7, wherein the central control unit ( 50 ) is designed as a battery management system and / or a transceiver circuit ( 20 ) and / or a line termination resistor ( 5 ), via which the central control unit ( 50 ) with the bus lines ( 38 . 39 ) of the bus system ( 40 ) connected is. Method for initializing a monitoring system ( 60 ), comprising a monitoring system ( 60 ) according to claim 7 or 8, wherein the method comprises the following method steps: - activating (S1) a first of the at least two monitoring circuits ( 30 ) via a via the hardware line ( 35 ) transmitted by the central control unit ( 50 ); Closing (S2) of the switching means ( 6 ) of the activated monitoring circuit ( 30 ) by the control electronics ( 10 ) of the activated monitoring circuit ( 30 ); Establishing (S3) a communication between the control electronics ( 10 ) of the activated monitoring circuit ( 30 ) and the central control unit ( 50 ); Assigning (S4) a unique identification number to the activated monitoring circuit ( 30 ) by the central control unit ( 50 ); - opening (S5) of the switching means ( 6 ) of the activated monitoring circuit ( 30 ) by the control electronics ( 10 ) of the activated monitoring circuit ( 30 ); - transmitting (S6) an activation signal via the hardware line ( 35 ) from the control electronics ( 10 ) of the activated monitoring circuit ( 30 ) to the control electronics ( 10 ) of another deactivated monitoring circuit ( 30 ); - restarting (S7) the method with the step of closing (S2) the switching means ( 6 ) of the further monitoring circuit ( 30 ). Method for initializing a monitoring system ( 60 ) according to claim 9, further comprising the step of terminating (S8) the method once all monitoring circuits ( 30 ) of the surveillance system ( 60 ) are activated. Method for initializing a monitoring system ( 60 ) according to claim 9 or 10, wherein the method of the central control unit ( 50 ) is controlled. Battery with a monitoring system ( 60 ) according to one of claims 7 or 8. Motor vehicle with a battery according to claim 12, wherein the battery is connected to a drive system of the motor vehicle.

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